Trough-edge building panel and method of manufacture

ABSTRACT

Disclosed herein is a trough-edge building panel used in the fabrication of panelized wall systems with elastomeric joints that are resistant to cracking. The panels are preferably fiber cement. The front surface of each panel has a trough adjacent to an edge of the panel. Panels are fastened to a frame with the trough-edges adjacent to each other. A joint tape is applied to the seam between the panels such that the edges of the joint tape fall within the troughs of the adjacent panels. The wall is then finished with an elastomeric finish. Also disclosed is a method of manufacturing the trough-edge panels.

RELATED APPLICATIONS

[0001] This application claims priority to U.S. Provisional PatentApplication Serial No. 60/333,967, filed Nov. 28, 2001, U.S. ProvisionalPatent Application Serial No. 60/334,138, filed Nov. 28, 2001, and U.S.Provisional Patent Application Serial No. 60/334,144, filed Nov. 28,2001, the disclosures of which are incorporated by reference in theirentireties.

BACKGROUND OF THE INVENTION

[0002] 1. Field of the Invention

[0003] The present application relates generally to building panels, andmore particularly, to trough-edge building panels useful in constructingpanelized wall systems with joints that are resistant to cracking.

[0004] 2. Description of the Related Art

[0005] Every building tradition in the history of mankind has producedstuccowork. Examples of stuccowork range from the Aztec architecture ofancient Mexico to the architecture of North Africa and Spain. In modemtimes, stuccowork has been popular in residential construction since the1920s, especially in dry, warm climates like the U.S. Southwest. Becauseof the many ways in which it can be treated, stucco remains a popularexterior finish for many building types. Since stucco is applied as apaste, it can be textured and will conform to almost any shape resultingin a smooth, seamless wall of monolithic appearance and sound structuralintegrity.

[0006] In spite of its ongoing popularity, many builders resist usingstucco as an exterior finish in framed construction because of theproblems associated with applying stucco to exterior walls.Traditionally, a stucco coating is a thin paste composed of Portlandcement, sand, lime, and water. Successive layers of stucco paste areapplied to a metal or plastic mesh fastened to the exterior of the wall.Stucco supported on framed construction is normally ⅞″ thick and isapplied in three applications: the first or scratch coat, the second orbrown coat, and the third, a finish, colored, texture coating. Sinceeach layer of stucco paste must dry and harden before the next isapplied, it takes several days to finish a traditional stucco wall.

[0007] While hundreds of thousands of new housing units are built everyyear, only a fraction of those units use stucco as an exterior finish.Stucco's susceptibility to moisture damage, for example, limits its usein wet climates. Likewise, stresses caused by transportingstucco-finished transportable buildings prevent its use in the lucrativemanufactured housing market.

[0008] Another method of producing a textured or stucco look is aDirect-applied Exterior Finish System or DEFS. In DEFS, panels of asubstrate material are fastened to the framing followed by a finishtexture coating. The texture coating may be applied as a single coat orin multiple thin coats, and often uses either a joint or full-wrapalkali-resistant fiberglass mesh to reinforce the coating againstcracking. DEFS can be installed and finished in a much shorter time thantraditional stucco, enabling shorter construction times.

[0009] DEFS have not enjoyed a large share of the exterior market,however, because thin DEFS coatings, which are relatively brittle, areincompatible with the movements of wall panels. The substrate panelswill invariably move with respect to each other from building settling,temperature variations, or moisture absorption. These movements cancause cracking of the finish at the panel joints. To prevent thiscracking, the joints are often covered with tape or filled with caulk.In many installations, both tape and caulk are used. In DEFS stuccoapplications over fiber cement, an alkali-resistant fiberglass meshtape, 2″ to 12″ wide, joins the two adjacent fiber cement panels thatare the substrate over which the stucco is applied.

[0010] One problem with these types of joints is “joint read,” aphenomenon in which the joint underlying the finish is visible. Jointread breaks the desired monolithic appearance of the finished wall.Joint read is a particular problem with fiber cement substrates becausefiber-cement-panel faces absorb moisture from the finish coat fasterthan the taped joint. This differential moisture absorption makes thejoint visible. In joints covered with tape, the step formed by the edgeof the tape and the panel surface can often be seen, especially withlow-angle illumination. Cracks arising from the loss of adhesion orslipping at the edges of the tape cause another type of joint read.

[0011] “Peaking” is another type of joint read and is caused by movementof the fiber cement panels. This movement causes the adhesive bondbetween the joint tape and the caulk joint to fail, causing the stuccoto separate from the caulk. As a result, the stucco covering the jointfloats higher or lower than the surrounding area, giving the appearanceof a peak. Peaking also results from the caulk shrinking during curing,pulling the adhered joint tape below the surface of the stucco. Peakingdisrupts the monolithic appearance of the wall and destroys theintegrity of both the stucco and the substrate.

[0012] Another option is a thin joint sealing tape. These tapes,however, are often waterproof. Consequently, they do not absorb thestucco mix, resulting in poor adhesion between the stucco and the tape,which leads to surface deformation.

[0013] A more serious problem is cracking at the joints. Cracking notonly disrupts the monolithic look of the finish, but also allowsmoisture to get behind the stucco and rot or corrode the wood or steelstructural framing. Furthermore, these cracks are entry points forinsects or fungi, which can damage the interior of the wall.

[0014] Consequently, DEFS are rarely used where there is wide dailytemperature variation especially when coupled with a high rate ofwet/dry cycling. DEFS are also seldom used in the fast-growingmanufactured housing market because of the additional stress placed onwalls during transport. Solving the joint read and stucco-crackingproblems could significantly expand the market for DEFS stuccoapplications using fiber cement and other substrates. Not only couldbuilders use fiber cement substrates and stucco in wetter climates, butalso fiber cement substrates and stucco use could be expanded to newmarkets such as manufactured housing and modular buildings.

[0015] One strategy for preventing cracking of a DEFS coating at thepanel joints is to construct joints from elastomeric materials. Theseelastomeric joints absorb the stress created by the differential panelmovements. Such joints may be used with flexible, latex-based texturecoatings, often called latex stucco or synthetic stucco. These finishesare able to move with the joint without cracking, which would greatlyexpand the market for DEFS applications.

[0016] The effectiveness of such joints may be evaluated in test wallsconsisting of several panels assembled on a frame, constructed with thejoint-to-be-tested. The test wall is finished with a DEFS coating andsubjected to a racking test. The racking test applies an in-plane shearforce to the test wall, resulting in relative panel movement, until theDEFS coating cracks. The distance of maximum deflection at which thefinish cracks is a measure of performance of the panel joints. Forexample, in order to pass the International Congress of BuildingOfficials (ICBO) AC 59 “Acceptance Criteria for Direct-Applied FinishingSystems” (September 1992), a test wall constructed according to themethod described in ASTM E-72 (98) subjected to a racking load thatcauses the wall to deflect 1″, does not develop any visible jointcracks.

[0017] The polymeric adhesives used,in joint tapes in DEFS tend tosoften and lose holding power at 120° F., a temperature often achievedon the exterior vertical walls of a building exposed to full summer sun.Fiber cement building panels may become saturated with water in wetenvironments if installed improperly or if the finish layer fails. Manyadhesives bond poorly to wet substrates. The performance of adhesivesused in manufacturing joint tapes for DEFS applications may be evaluatedusing the “180° peel test,” a well-known method of evaluating theadhesive strengths of tapes. The 180° peel test measures the forcerequired to break the adhesion of a joint tape applied to two substratesheld at a 180° angle.

[0018] U.S. Pat. No. 5,732,520 describes a method for forming asingle-coat, synthetic-stucco-finished exterior wall. First, fibercement wallboard panels are installed onto a building frame with theadjacent edges of the panels forming narrow gaps. Polyurethane caulk isapplied to the gaps, and low-profile fabric-backed joint tape is appliedover the adjacent edges of the panels to cover the gaps and the caulk. Ahigh build flexible resinous latex emulsion in next applied directlyover the panels and adhesive tape to form a synthetic stucco finish. Themoisture absorption properties of the fabric from which the tape ismanufactured matches that of the wall panels. A stucco-finished jointconstructed according to this patent with 3″-wide joint tape slips andcracks at the edges when stretched 3-5 mm. The relative motion ofadjacent 4′×8′ cementitious boards under normal conditions is greaterthan 3-5 mm, however. While the joint tape described in U.S. Pat. No.5,732,520 distributes the joint movement somewhat, the adhesive used inthis tape is not sufficiently strong to prevent the edges of tape fromslipping under stress. Consequently, the edges of the tape slip,cracking the stucco coating. A wider tape, for example, a 6″-wide tape,might better withstand the movement, but at an increased cost.

[0019] Cracking may be also prevented by applying additional layers ofstucco or a joint compound over the tape before applying the final coatof stucco. This method, however, is expensive, time consuming, andrequires skilled workers. Moreover, this technique often fails toproduce satisfactory results. Another method of preventing cracks isincreasing the thickness of the stucco build. This method is alsoexpensive and time consuming, however.

SUMMARY OF THE INVENTION

[0020] The present disclosure provides trough-edge building panels andmethods of their manufacture. The trough-edge panels are useful in theconstruction of walls with elastomeric joints that are resistant tocracking.

[0021] Accordingly, one embodiment provides a trough-edge building panelcomprising: a building panel comprising a front surface, a back surface,and a plurality of edges and a trough on the front surface of the panelextending along an edge of the panel, wherein the trough is spacedinwardly from the edge of the panel by a trough edge offset, the troughis sized and configured to accept an edge of a backing material appliedover a seam between adjacent panels, and the trough comprises a wall anda floor, wherein a side of the trough proximate to the edge of the panelforms the wall, wherein the height of the wall is a trough depth, thefloor of the trough is lower than a surface of the panel between thewall of the trough and the edge of the panel, and the width of the flooris a trough width.

[0022] In a preferred embodiment, the panel is fiber cement. Preferably,the trough-edge panel is about 4′ by about 8′. The panel is preferablyfrom about {fraction (3/16)}″ to about 2″ thick. In a second preferredembodiment, the trough-edge panel has a trough edge offset of from about½″ to about 3″, a trough depth of from about 0.005″ to about 0.25″, anda trough width of from about ⅛″ to about 2″. The trough-edge panel mayfurther have a surface offset depth of from 0″to about 0.1″. The troughis preferably formed by embossing, using a plate press, using a profiledaccumulator roll in the Hatschek process, or by post-cure machining.

[0023] Another embodiment provides a method of fabricating a trough-edgebuilding panel comprising at least the step of creating a trough on thefront surface of a building panel extending along an edge of a panel,wherein the trough is spaced inwardly from the edge of the panel by atrough edge offset, the trough is sized and configured to accept an edgeof a backing material applied over a seam between adjacent panels, andthe trough comprises a wall and a floor, wherein the side of the troughproximate to the edge of the panel forms the wall, wherein the height ofthe wall is a trough depth, the floor of the than the surface of thepanel between the wall of the trough and the edge of he width of thefloor is a trough width.

[0024] In a preferred embodiment, the panel is fiber cement. Preferably,the trough-edge panel is about 4′ by about 8′. The panel is preferablyfrom about {fraction (3/16)}″ to about 2″ thick. In a second preferredembodiment, the trough-edge panel has a trough edge offset of from about½″ to about 3″, a trough depth of from about 0.005″ to about 0.25″, anda trough width of from about ⅛″ to about 2″. The trough-edge panel mayfurther have a surface offset depth of from 0″ to about 0.1″. The troughis preferably formed by embossing, using a plate press, using a profiledaccumulator roll in the Hatschek process, or by post-cure machining.

BRIEF DESCRIPTION OF THE DRAWINGS

[0025]FIG. 1 is a photograph of a conventional fiber cement panel seam.

[0026]FIG. 2 is a photograph of an example of seam failure due tocracking on a conventional synthetic stucco application.

[0027]FIG. 3 is a photograph illustrating “peaking” at a fiber cementpanel seam.

[0028]FIG. 4 is a top view of a trough-edge building panel.

[0029]FIG. 5 is a cross section of a trough-edge building panel.

[0030]FIG. 6 is a cross section of an alternative embodiment of atrough-edge building panel.

[0031]FIG. 7 is a cross section of an elastomeric joint formed at theseam of adjacent trough-edge panels.

[0032]FIG. 8 is a key for the dimensions in TABLE 1 for a trough-edgebuilding panel.

[0033]FIG. 9A and FIG. 9B are cross sections of a first embodiment of abuilding panel with an embossed edge and an elastomeric joint using thepanel.

[0034]FIG. 10A and FIG. 10B are cross sections of a second embodiment ofa building panel with an embossed edge and an elastomeric joint usingthe panel.

[0035]FIG. 11A and FIG. 11B are cross sections of a third embodiment ofa building panel with an embossed edge and an elastomeric joint usingthe panel.

[0036]FIG. 12A and FIG. 12B are cross sections of a fourth embodiment ofa building panel with an embossed edge and an elastomeric joint usingthe panel.

[0037]FIG. 13 is a cross section of a first embodiment of an elastomericjoint made according to METHOD 1-METHOD 10.

[0038]FIG. 14 is a cross section of a second embodiment of anelastomeric joint made according to METHOD 1-METHOD 10.

[0039]FIG. 15 is a flowchart illustrating METHOD 1 for making anelastomeric joint.

[0040]FIG. 16 is a flowchart illustrating METHOD 2 for making anelastomeric joint.

[0041]FIG. 17 is a flowchart illustrating METHOD 3 for making anelastomeric joint.

[0042]FIG. 18 is a flowchart illustrating METHOD 4 for making anelastomeric joint.

[0043]FIG. 19 is a flowchart illustrating METHOD 5 for making anelastomeric joint.

[0044]FIG. 20 is a flowchart illustrating METHOD 6 for making anelastomeric joint.

[0045]FIG. 21 is a flowchart illustrating METHOD 7 for making anelastomeric joint.

[0046]FIG. 22 is a flowchart illustrating METHOD 8 for making anelastomeric joint.

[0047]FIG. 23 is a flowchart illustrating METHOD 9 for making anelastomeric joint.

[0048]FIG. 24 is a flowchart illustrating METHOD 10 for making anelastomeric joint.

[0049]FIG. 25 is a cross section of an elastomeric joint made accordingto METHOD 11.

[0050]FIG. 26 is a flowchart illustrating METHOD 11 for making anelastomeric joint.

[0051]FIG. 27 is an elevation of a panelized wall system withelastomeric joints.

[0052]FIG. 28 is a flowchart illustrating a method of fabricating apanelized wall system with elastomeric joints.

[0053]FIG. 29 illustrates the comparative performances of a wallconstructed according to U.S. Pat. No. 5,732,520 and a wall constructedaccording to the present disclosure in a racking test.

[0054]FIG. 30 is a cross section of a joint tape.

[0055]FIG. 31A and FIG. 31B are top and cross-sectional views of anadhesive-edge panel.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0056] Disclosed herein is a system for constructing, from substratepanels, walls with synthetic stucco finishes that resist cracking.Embodiments of the disclosed wall system are constructed fromcombinations of the components defined below.

[0057] Definitions

[0058] Joint. The term “joint” as used herein refers both to a structureformed by the edges or comers of adjacent building panels, and a systemof components used to fill or cover this structure. The intended meaningwill be clear by context. The term “seam” is used interchangeably withthe first sense of “joint,” but not the second. A “joint” in the firstsense or “seam is formed by two adjacent panels that have no gap betweenthem, i.e., butted together, or with a gap between them.

[0059] Building Panels. The building panels of the present applicationare made from substrates suitable for interior or exterior construction.The panels may be flat or embossed, and may also have textured surfaces.The substrate may be inorganic, organic, or a combination thereof. Fiberreinforced inorganic substrates are preferred, for example glass matreinforced cement boards, glass mat reinforced gypsum boards, andmaterials such as Georgia Pacific's Dens-glass Gold and United StatesGypsum's Aquatough. It will be appreciated, however, that the method maybe applicable to other fiber reinforced inorganic substrates as well asother substrates, including but not limited to aluminum, other cementcomposites such as scrimboard, wood, plywood, oriented strand board(OSB), wood composites, gypsum boards such as described in U.S. Pat. No.5,718,759, the entirety of which is incorporated by reference, andplastics such as polymer foam composite panels such as expandedpolystyrene foam.

[0060] A particularly preferred substrate is fiber cement (FC). Fibercement panels can be fabricated by conventional methods, for example,the Hatschek process. Fiber cement panels can be either pretreated oruntreated with a coating to modify water absorption through the panelface. Fiber cement panels can also be treated with a sealer, primer, orother coating.

[0061] While the components of the disclosed embodiments of theinvention are selected to best work with fiber cement panels, it will beappreciated that similar components can be selected to achieve the sameperformance when used with building panels composed of other substrates.

[0062] Caulk. In those embodiments using caulk, the caulk is preferablya high solids, non-shrinking, permanently flexible caulk made from 100%polymer, such as a moisture cure polyurethane, moisture curesilicone-based adhesive, and silane-based adhesive. More preferably, thecaulk is a 100%-solid moisture-cure polyurethane that has good adhesionto the cementitious boards, to the adhesive applied to the backingmaterial, and to the backing material. An example of a suitable 100%polyurethane caulk such is Chem-calk 900 (Bostik Findley).

[0063] Adhesives. As described hereinafter, an adhesive layer isdisposed between the building panel and a backing material. Elastomericadhesives having long elongation are preferred adhesives. Preferably,the elongation is greater than about 20%. An adhesive layer preferablyhas a certain thickness that allows it to slip and distribute themovement of the panels to the entire backing material, preventingcracking of the finish coat. Thicker and softer adhesive layersgenerally slip more easily, although the minimum thickness required toprovide the desired slip characteristics will vary for each differentadhesive. A preferred adhesive layer thickness is from about 0.001″ toabout 0.04″. A thinner adhesive layer is easier for the finish to hide,however, and may be preferred to provide a superior finish. The adhesivelayer may include a single adhesive or several adhesives, for example, adual adhesive system.

[0064] The elastomeric joints disclosed herein use an adhesive that iselastomeric, distributing the movement of the panels to the entirebacking material. In certain embodiments, the adhesive also anchors theedges of the backing material to the building panel, preventing theedges from slipping. The adhesive may be a pressure-sensitive ornon-pressure-sensitive adhesive. The former class of adhesives isparticularly preferred. These adhesives are normally tacky at roomtemperature and adhere to a surface by application of light fingerpressure. In another embodiment, a hot-melt adhesive is preferred.

[0065] The adhesive may include water-based, solvent-based, and 100%solid-based adhesives. Preferred adhesives include one-component andtwo-component adhesives. The adhesive may be based on, for example,general compositions of polyacrylate, polyvinyl ether, rubber (e.g.,natural rubber), isoprene, polychloroprene, butyl rubber, neoprenerubber, ethylene propylene diene rubber (EPDM), polyisobutylene,butadiene-acrylonitrile polymer, thermoplastic elastomers,styrene-butadiene polymer, poly-alpha-olefin, amorphous polyolefin,silicone, ethylene-containing copolymer (e.g., ethylene vinyl acetate,ethylene ethyl acrylate, ethylene n-butyl acrylate, and ethylene methylacrylate), polyurethane, polyamide, epoxy, polyvinylpyrrolidone andpolyvinylpyrrolidone copolymers, polyesters, and mixtures or copolymersthereof. The adhesive layer may also contain additives or modifiers, forexample, tackifiers, plasticizers, fillers, antioxidants, stabilizers,pigments, curatives, crosslinkers, solvents, etc.

[0066] Certain embodiments of the present invention further comprise asecond adhesive. The second adhesive is relatively more rigid than thefirst adhesive. The rigid second adhesive, applied at the edges of thebacking material, anchors the edges of backing material to the panels,preventing cracking of the finish at the edges of the backing material.

[0067] The second adhesive may be selected from the same class ofadhesives as the first adhesive, i.e., pressure-sensitive ornon-pressure-sensitive adhesives; hot-melt adhesives; water-based,solvent-based, and 100% solid-based adhesives; and one-component andtwo-component adhesives. Preferred second adhesives include, but are notlimited to, water-based and solvent-based acrylic adhesives, modifiedacrylic adhesives, formaldehyde-based adhesives, moisture-curepolyurethanes, two-part polyurethanes, two-parts epoxies, one-part andtwo-part silicone-based adhesives, natural adhesives such as starch andprotein, inorganic adhesives, polymer-latex adhesives, and mixturesthereof. In another preferred embodiment, the finish coat is the secondadhesive. In this embodiment, the backing material is permeable to thefinish coat, allowing the finish to adhere directly to the panelsubstrate beneath the backing material.

[0068] The first and second adhesives may be applied by solvent coating;extrusion, either separately from or simultaneously with the backingmaterial; hot melt coating; calendaring; curtain coating; gravure orpattern coating; spray coating; lamination; pressure feed die coating;knife coating; roller coating; or any other suitable technique. It isexpressly contemplated that the adhesive layers can be eithercontinuous, such as a uniform layer, or discontinuous, such as strips orbands, dots, or another patterned or random arrangement of discreteadhesive portions. The thickness of adhesive is controlled according tothe requirements of the application.

[0069] Preferred first and second adhesives includestyrene-isoprene-styrene block-copolymer adhesives, for example PL919pressure sensitive adhesive (SIA Adhesives); styrene-butadiene polymeradhesives, for example H400 pressure sensitive adhesive (HeartlandAdhesives & Coatings); and butyl rubber adhesives, for example PVT-3300(Carlisle Coating & Waterproofing) and HL 2203 (H. B. Fuller). Anotherpreferred second adhesive is a polyurethane adhesive, for exampleUR-0210 moisture-cured polyurethane (H. B. Fuller).

[0070] Backing Material. The backing material is a fabric or film towhich the adhesive components of the disclosed panelized wall systemsadhere, i.e., the adhesives, caulk, joint filler, ceramic putty, andfinish coating, particularly cement-based stucco coatings andlatex-based texture coatings. Preferably, the backing material stretchesand moves with the building panels without tearing the backing materialand without cracking the finish coating covering the backing material.Preferred backing materials include, but are not limited to, cellulosepapers, plastic films, metal foils, and woven or non-woven fabrics.

[0071] Of these materials, fabric is preferred. Preferred fabrics arepolyester, polypropylene, polyethylene, polyamide, cellulose, cotton,rayon, glass fiber, or combination of two or more of these materials.Preferably, the backing material has a selected moisture absorptioncharacteristic that provides a monolithic appearance to the finish coat.The fabric should adhere well to the joint filler compounds and texturecoatings of the disclosed panelized wall system. A preferred backingmaterial is made from a non-woven polyester fabric, for example Sontara(Dupont). Sontara 8801 is 16 mil (0.016″) thick, Sontara 8000 is 20 mil(0.020″) thick, and Sontara 8004 is 25 mil (0.025″) thick. Particularlypreferred are backing materials made from a non-woven polyester fabricthat is greater than about 16 mil thick. Another preferred backingmaterial is made from a polyamide (Nylon) mesh fabric.

[0072] Preferred backing materials are easily bonded by the adhesivesused herein, with good adhesion under dry, equilibrium, and water-soakedconditions, and at different temperatures. Preferably, the backingmaterial has an elongation of about 20% or more, more preferably fromabout 20% to about 500%, wherein the preferred range includeselongations of about 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%,70%, 75%, 80%, 85%, 90%, 95%, 100%, 110%, 120%, 130%, 140%, 150%, 160%,170%, 180%, 190%, 200%, 210%, 220%, 230%, 240%, 250%, 260%, 270%, 280%,290%, 300%, 320%, 340%, 360%, 380%, 400%, 420%, 440%, 460%, 480%, and500%.

[0073] A very thin fabric backing material may not be sufficientlystrong to maintain a solid joint. On the other hand, a thick fabric maybe difficult to hide beneath the finish. A preferred fabric thickness isfrom about 0.0005″ to about 0.04″, more preferably from about 0.001″toabout 0.03″. A preferred width of backing material is from about ¼″ toabout 12″. A more preferred width of backing material is from about ½″to about 8″. A very narrow backing material may not sufficiently coverany gaps between the panels or effectively distribute the panelmovements. A very wide backing material is less cost effective.

[0074] Joint Fillers. Certain embodiments of the disclosed elastomericjoint include one or more joint fillers applied over the backingmaterial, adhesive layers, any troughs, and embossed edges or other edgeprofiling on the building panels. The joint filler fills any depressionsin the joint or trough areas, providing a smooth surface for the texturecoating. The joint filler preferably has elastomeric propertiesspecifically selected to complement the expansion and contractioncharacteristics of the elastomeric tape applied beneath and finishcoatings applied above the joint filler. The joint filler is preferablya mixture that includes a polymer binder, one or more inorganic fillers,thickeners, pigments, and inorganic binders.

[0075] Polymer latex emulsions such as acrylic emulsions are well knownin the art and are suitable as the elastomeric polymer binder. Othersuitable polymer binders include redispersable powdered acrylics,polyurethanes, and silicones.

[0076] Inorganic binders can be used in the joint filler material toprovide hardness and scratch resistance. One example of a suitableinorganic binder is a combination of soda lime glass and acrylic acid,in which the soda lime glass reacts with the acrylic acid to form a gel.As this gel dries, it hardens the joint filler material.

[0077] Calcium carbonate, kaolin clay, aluminosilicate, and othersilicate minerals are examples of suitable inorganic fillers, as arewell known in the art. The inorganic filler may also be a low-densityexpanded mineral such as perlite. Hollow aluminosilicate or polymericmicrospheres are examples of inorganic fillers that both modify thedensity of the joint filler and control the expansion and contractioncharacteristics.

[0078] Suitable thickeners are well known in the art, and includecellulose ethers, vegetable gums, clays, and synthetic polymers such asammonium salts of acrylic polymers.

[0079] Pigments may be white, for example titanium dioxide, kaolin clay,or calcium carbonate, or colored, for example iron oxides. Pigmentssuitable for coloring the joint filler are well known in the art.

[0080] The joint filler may be smoothed over the joint by any methodknown to the art, for example by using a trowel and float. Typically,the joint filler is applied in one or more thin layers in order tominimize the visibility of the joint. As will become apparent below, thethickness of the joint filler application depends on a variety offactors including the thickness of the backing material, the thicknessof the adhesive, the presence or absence of trough edges on the panels,and the presence or absence of other edge features on the panels. Onceapplied, the joint filler is typically allowed to cure (harden) for 1-4hours, depending on temperature and humidity conditions. After curing,the joint filler may be smoothed by sanding. A preferred joint filler isa ceramic putty, for example Fill-n-Build (Global Coatings), whichcontains by weight acrylic copolymer emulsion (30%), hydrated aluminumsilicate mineral (19.5%), soda lime borosilicate glass (10%), kaolinclay (8%), titanium dioxide (4%), and ammonium salt of acrylic polymer(1%).

[0081] Certain disclosed embodiments use an elastomeric joint filler,which provides an elastomeric surface to the exterior face of the joint.An elastomeric joint filler contains a higher proportion of polymer tomake it more elastomeric, and is typically smoothed over the surface ofthe joint using a trowel and float and allowed to cure for about 1-4hours, depending on temperature and humidity. A preferred elastomericjoint filler is Acracream (Global Coatings), which contains by weightacrylic polymer emulsion (55%), calcium carbonate (30%), polymericmicrospheres (3.9%), and titanium dioxide (2%).

[0082] The elastomeric joint in certain embodiments of the presentinvention includes an elastomeric joint filler applied over a ceramicputty. Preferably, the elastomeric joint filler is selected to match theelastomeric properties of the synthetic stucco coating, furtherenhancing the crack resistance of the joint.

[0083] Finish. The finish is preferably an elastomeric finish and may beapplied by any means suited to the particular finish, for example,troweling, spraying, rolling, or brushing. The finish coating is alsoreferred to as “finish” and “surface coating.”

[0084] A preferred finish is a textured finish simulating stucco,selected for its water resistance and flexibility. This type of finishis referred to as “synthetic stucco” or simply “stucco.” Such finishesare well known in the art and are generally contain a polymer binder,inorganic filler, water, and pigments. Texture coatings are generallyapplied with a spray gun in one or more coats, for example, a primer anda texture layer, which are allowed to dry between coats. Commerciallyavailable synthetic stucco finishes compatible with the disclosedpanelized wall systems include Multitex (Multicoat, Costa Mesa, Calif.),Akro-Gold (Omega Products), and Harditexture (James Hardie, Fontana,Calif.).

[0085] Suitable finish coats may also be applied by other means. Forexample, Colorseal Plus (Global Coatings) is applied to the entire wallusing a paint roller and allowed to dry for 1 to 2 hours, providing asurface of uniform moisture absorption properties and uniform color. Thecomposition of Colorseal Plus is typical and contains by weight aqueousacrylic emulsion (39%), calcium carbonate (35%), water (19%), titaniumdioxide (5%).

[0086] A final coating of Carrara texture-coat is then shot onto thewall with a hopper gun. The surface may be left “as is” for a roughfinish, or hand-troweled to the desired smoothness. The finish isprotected until cured, typically 8-24 hours.

[0087] Frame. As used herein, a frame is any frame capable of supportingthe disclosed panelized wall system. Preferred frames are wood or metalframes. Preferably, the vertical members of the frame are spaced about16″ apart, up to about 24″ apart or more, and optionally wrapped in amoisture barrier.

[0088] Another preferred frame is a shear wall, a frame to which shearpanels, typically plywood or oriented strandboard (OSB) panels, areattached for reinforcement. Other examples of a suitable frame include atilt-up wall, or a previously finished wall, such as wall finished witha cladding.

[0089] Preferably, the building panels are positioned on the frame withthe edges of adjacent panels sharing a common framing member, forexample, a stud. In some embodiments, the panels are positioned with agap of predetermined width between adjacent panels, the gap fallingdirectly over a framing member. In another embodiment, the panels areinstalled without gaps, i.e., butted edge-to-edge. In embodiments withgaps between adjacent panels, the width of the gap is preferably fromabout {fraction (1/16)}″ to about ⅛″, allowing for building and panelmovement, and shrinkage and expansion of the building panels. The bottomedges of the wall panels are preferably positioned on the wall level toensure that the panels are level and plumb.

[0090] The building panels may be attached to the frame by any meansknown in the art. Mechanical means include nails, screws, staples, nutsand bolts, clips, and the like. The panels may also be fastened to theframe with chemical means, for example, with an adhesive or a tape. Apredetermined pattern of fasteners is typically used to fasten thebuilding panels to the frame. Preferred fasteners are screws and nails.

[0091] Moisture Barriers. Moisture barriers are used in certainembodiments of the disclosed panelized wall systems. Any type ofmoisture barrier, also called water barriers and weather-resistivebarriers, known in the art may be used, for example asphalt paper,polyethylene-based sheeting, reinforced plastic sheeting, or foaminsulation panels. A preferred moisture barrier is asphalt paper, alsocalled asphalt-impregnated paper. The moisture barrier is installedbetween the frame and the building panels.

[0092] Water Management Systems. Certain embodiments of the disclosedpanelized wall systems comprise water management systems, for example,water breaks, rain screens, or weep screens. Preferred water managementsystems are designed for use under panelized substrates, for exampleHomeslicker Rain Screen (Benjamin Obdyke, Horsham, Pa.). The watermanagement system is typically installed beneath the building panels

[0093] Release Liner. A release liner or release paper is a paper orplastic film coated with a release agent. The release liner is laminatedto an adhesive layer, protecting the adhesive layer. A preferred releaseagent is a silicone-based polymer. The thickness of release liner ispreferably from about 0.0002″ to about 0.005″. The release liner is easyto be peeled from the adhesive layer in order to expose the adhesive.

[0094] Testing. Tensile testing was performed on sample elastomericjoints made from 2″×5″×{fraction (5/16)}″ specimens of primedfiber-cement panel (Hardipanel, James Hardie, Fontana, Calif.). Thesample joints were fabricated on the 2″ sides of two panel specimens. Intest samples with caulked joints, the caulk was a 100% polyurethanecaulk (Chem-calk 900, Bostik Findley). The caulk was applied to a ⅛″ gapbetween the panels, the caulk surface smoothed, and the caulk allowed tocure overnight. The test samples were finished with a medium texture({fraction (1/16)}″) elastomeric latex stucco (MultiTex, Multicoat,Costa Mesa, Calif.). The thickness of the texture coating varied withthe texture pattern, from about 0″ to about {fraction (1/16)}″.

[0095] Tensile testing was performed on a universal test machine(Instron). In the tensile tests, a sample test joint was mounted in thetesting machine and stretched, typically at 6 mm/min, until the finishcoating cracked. The strain of the joint at failure was calculated fromthe sample geometry and machine crosshead displacement.

[0096] Elastomeric Joints

[0097]FIG. 1 is a photograph of a conventional fiber cement panel joint100. Panel joint 100 comprises two adjacent fiber cement substratepanels 110 separated by a ⅛″ gap at the seam 120 and covered by tape130.

[0098]FIG. 2 is a photograph of a conventional synthetic stuccoapplication 200. The stucco finish typically has a number of valleys210. Valleys 210 are particularly susceptible to joint read, wherecracks like crack 230 form near the joint 220. The cracks are caused bythe movement between the fiber cement panels and the tape that joins twopanels together beneath the stucco.

[0099]FIG. 3 is a photograph of a synthetic stucco application wherepeaking has occurred. Peaking is caused by movement of the fiber cementpanels, more particularly, environmentally induced expansion andshrinkage. This movement causes failure of the adhesive bond between thesubstrate and the joint tape and caulk, causing the stucco over thejoint to float higher or lower than the stucco over the field of thepanels.

[0100] One embodiment of the present invention provides a building panelwith a trough adjacent to an edge of the panel. These trough-edge panelsin conjunction with a joint tape create an elastomeric joint that isresistant to cracking at or near the joint and minimizes joint readcaused by the height differential between the panel and the edge of thejoint tape that covers the seam between adjacent panels. The panel isdesigned such that the edge of the joint tape lies in the trough,concealing the edges below the surface plane of the panel, such that thefinish coat provides a uniform, flat finish.

[0101]FIG. 4 and FIG. 5 are top and cross sectional views, respectively,of a fiber cement panel 410 with a trough 420 according to oneembodiment of the present invention, which overcomes the joint read andcracking problems illustrated in FIG. 2 and FIG. 3. The trough 420 isspaced inwardly from the edge 450 of the panel. In one embodiment, theside of the trough 420 closer to the edge 450 of the panel forms a wall430, the wall meeting a floor 440 lower than the surface 460 of thepanel between the trough 420 and the edge 450 of the panel. Theembodiment illustrated in FIG. 5 also has a second wall 470 opposite tothe first wall 430 that also meets the floor 440, forming asubstantially rectangular trough 420. The edge of the joint tapepreferably lies on the floor 440 of the trough 420. In a preferredembodiment, the trough 420 is spaced inwardly from the edge 450 of thepanel by a distance χ of about 1″. In this embodiment, the trough 420has a rectangular cross section with a width α of about 0.63″ and adepth β of about 0.034″. In another preferred embodiment, the trough 420extends to the edge of the panel such that trough 420 does not include awall 430. FIG. 6 illustrates yet another embodiment in which the surface460 between the trough 420 and the edge 450 of the panel slopesdownwards towards the edge 450. The sloped surface reduces peaking inelastomeric joints that use caulk between the panels.

[0102] Fiber cement panel 410 may be fabricated by any method known inthe art, for example, by the Hatschek process. The trough 420 may beformed by embossing, using a plate press, using a profiled accumulatorroll in the Hatschek process, or by post-cure machining, as describedbelow. The edges of the tape fall below the surface of the fiber cementpanels 410, preventing joint read. The trough 420 illustrated in FIG. 5and FIG. 6 has a rectangular cross section; however, it will beappreciated that the trough may assume other shapes, as described below.

[0103]FIG. 7 illustrates a joint incorporating a trough-edge panel. Thissystem includes two adjacent panels 710 separated by a gap. In theillustrated embodiment, caulk 720 is applied to the gap. It will beappreciated that the gap and/or caulk are optional. For example,adjacent panels may be separated by a gap that is not caulked. Apreferred embodiment described below, has neither a gap nor any caulkbetween adjacent panels. Tape 750 is applied over the edges of thepanels 710, with the edges 755 of the tape falling inside the troughs760 of the panels 710. Synthetic stucco 780 is applied over the panels710 to cover the tape 750.

[0104]FIG. 8 is keyed to the dimensions of a preferred panel substrateprovided in TABLE 1 below. TABLE 1 Feature Reference Preferred RangePreferred Board Thickness A about {fraction (3/16)}″-2″ about {fraction(5/16)}″ Trough Edge Offset B about ½″-3″ about 1½″ Trough Width C about⅛″-2″ about ¾″ Trough Depth D about 0.005″-0.25″ about 0.050″ TroughRelief Angle ∠E  about 5°-90° about 45° or rounded Surface Offset Fabout 0-0.1″ about 0.010″ Depth Edge Taper Width G about 0-0.25″ about0.060″ Edge Taper Depth H about 0-0.25″ about 0.060″ Edge Taper Angle∠I  about 0-90° about 15° Edge Thickness J about {fraction (3/16)}″-2″about {fraction (5/16)}″

[0105] TABLE 1 provides preferred dimensions for fiber cement buildingpanels. The board thickness A is selected for the particular buildingapplication. Thicker panels are stronger, but are heavier and moredifficult to handle, more expensive, and require more warehousing space.The trough edge offset B and trough width C are selected such that theedges of the selected joint tape fall within the troughs of adjacentpanels. Widening the trough width C allows for a greater range of jointtape widths to be used with a particular panel, as well as flexibilityin providing a gap or no gap between adjacent panels. Without beingbound by any theory, our current belief is that the motion of the panelsis accommodated by that part of the tape outside the troughs, however.Accordingly, a narrower trough width C would provide a more flexiblejoint. Moreover, a narrow trough requires less joint filler or surfacefinish to fill, facilitating hiding the joint. The preferred dimensionsfor the trough edge offset and trough width contemplate a 3″-wide jointtape and either no gap or a gap no wider than about ⅛″ between adjacentpanels. The trough depth D is selected such that the top of the jointtape within the trough is approximately level with the board thicknessA. Consequently, the preferred trough depth approximates the thicknessof the joint tape. A trough relief angle E less than 90° makes hidingthe joint easier. A shallower angle or rounded edge minimizes thevisibility of the trough wall. The surface offset depth F reduces thepanel thickness A to the edge thickness J, further reducing the changesin elevation in the taped joint, and again, reducing the visibility ofthe joint. The edge panel width G, depth H, and angle I are selected toreduce peaking in caulked joints. It will be appreciated that thefeatures and dimensions illustrated in TABLE 1 are merely exemplifying,and thus, the panel can have other features and dimensions. For example,the very edge of the board can be cut with multiple angles, which mayassist in eliminating peaking and/or the need for caulk.

EXAMPLE 1 Comparative Testing of Joint Flexibility for Trough-EdgePanels

[0106] Tensile testing of the flexibilities of joints constructed frompanels with different embossed trough depths was performed on auniversal testing machine at a strain rate of about 5 to 10 mm perminute. Three different joint configurations were tested on a substrateof {fraction (5/16)}″-thick fiber-cement panel (Hardipanel, JamesHardie, Fontana, Calif.). Each joint was caulked, taped with 3″-widetape, and finished with a synthetic stucco finish. The joints werecaulked with a 100% urethane caulk (Chem-calk, Bostik Findley), tapedwith a 3″-wide elastomeric tape (Multicoat Elastomeric Joint Tape,Multicoat, Costa Mesa, Calif.) centered over the joint, and finishedwith a medium grit worm finish synthetic stucco (MultiTex, Multicoat,Costa Mesa, Calif.). In the panels with troughs, the troughs were spacedsuch that the edges of the tape fell within the troughs.

[0107] The testing results reported in TABLE 2 demonstrate the improvedjoint flexibility provided by joints made with trough-edge panelscompared to those made with flat panels. The trough depths were selectedto provide joint flexibility while maintaining an aestheticallyacceptable appearance. In test A, the control, the panels were smoothwith no edge trough. In test F, each panel was embossed with a singleshallow batten with a rectangular cross section approximately 0.077″deep running the length of the panel. In test E, each panel was embossedwith a single deep batten with a rectangular cross section approximately0.086″ deep running the length of the panel. In both trough-edge panels,the troughs edge offset (B) was 1½″ and the trough width (C) was ¾″.

[0108] As shown in TABLE 2, the panel with the shallow trough (test F)provided the most flexible joint system, stretching 10.48 mm (13.8%)before failing. In each case, the joint failed when the edge of the tapeslipped from the panel surface at the top and bottom of the tape. In nocase did the joint fail at the seam between the panels. TABLE 2 TestTrough Depth Tensile Joint Stretch to Failure A No Trough 4.58 mm (6.0%)F 0.077″ 10.48 mm (13.8%) E 0.086″ 9.01 mm (11.8%)

[0109] The results provided in TABLE 2 demonstrate that the jointflexibility as determined by joint stretch, more than doubled in thetrough-edge joint F compared to the smooth, flat panel joint A. Thisgreater flexibility translates into increased resistance to jointcracking. The added stucco finish used to conceal the trough alsoconceals the edges of the tape, reducing joint read. The trough-edgejoint also demonstrated improved shear strength of the DEFS coating.

[0110] Irrespective of the thinness of a joint tape or backing material,when used on a flat panel, there will be a height difference between thetop of the joint tape or backing material and the surface of the panel.FIG. 9-FIG. 12 illustrate panels with embossed edges designed to providean improved finish. Preferably, the depth “a” of the embossed edge isthe same as the thickness of the backing material and adhesives.Preferably, twice the width “b” of the embossed edge plus the width ofany gap between adjacent panels equals the width of the backingmaterial. The top surface of the backing material and the front surfaceof the panels are preferably coplanar, resulting in a monolithicappearance even when using a thin finish coat.

[0111] The embossed edge may be flat as in FIG. 9. It may be sloped asin FIG. 10 and FIG. 11, or have steps as in FIG. 12, or have curvedprofile (not shown), or any combination thereof. The transition betweenthe side-wall and bottom of the embossed edge may be a sharp angle as inFIG. 9-FIG. 12 or curved (not shown). Panels with embossed edges mayalso comprise edge troughs as described above. The disclosed methods offabricating elastomeric joints are applicable to flat panels, panelswith embossed edges, trough-edge panels, and trough-edge panels withembossed edges.

[0112] For fiber cement panels, the embossed edges are preferablyproduced by embossing, although they may also be produced by othermethods, for example by using a plate press, using a profiledaccumulator roll in the Hatschek process, or by post-cure machining.

[0113]FIG. 13 and FIG. 14 are cross-sectional views of elastomericjoints 900 that include two adjacent panels 910; optionally, a caulk920; a first adhesive 930; a second adhesive 940; a backing material950. Certain embodiments of the elastomeric joint may also have a jointfiller, as is discussed in greater detail below. The panels may be flat,as shown in FIG. 13; have trough edges 960, as shown in FIG. 14; haveembossed edges (not shown); or a combination thereof. The surface iscovered with an elastomeric finish 980, preferably, a texture coating orsynthetic stucco finish. Adhesive 930 is at the center of the joint andadhesive 940 is at the edges of the joint. The adhesives and backingmaterial distribute the panel movement from the seam formed by thepanels to the entire backing material greatly reducing strain on thefinish coating, which prevents cracking of the finish.

[0114] The caulk 920 fills the gap between adjacent panels 910. Itprovides a surface for the elastomeric adhesive or adhesives appliedthereover, supporting the adhesives, backing material, and texturecoating under tensile and compressive forces across the joint. A jointwithout caulk may show peaking at the joint or cracking in the coating.

[0115] The adhesive layer may include a single adhesive or dualadhesives. FIG. 13 and FIG. 14 illustrate a dual adhesive system. In asingle adhesive system, adhesives 930 and 940 are the same adhesive. Ina dual adhesive system two different adhesives are used. As shown inFIG. 13 and FIG. 14, a first adhesive 930 used in the central part ofthe joint is relatively more flexible than a second adhesive 940 used atthe edges of the joint. The more flexible first adhesive 930 distributesthe panel movements across the entire backing material 950, while themore rigid second adhesive 940 anchors the edges of the backingmaterial, preventing cracks that arise from tape slippage.

[0116] EXAMPLE 2 and EXAMPLE 3 below illustrate the advantages of usingboth an adhesive layer and a backing material in an elastomeric joint.In EXAMPLE 2, the joint is fabricated without an adhesive layer. InEXAMPLE 3, the joint has no backing material. Neither joint successfullywithstood significant panel movement.

EXAMPLE 2 Joint Without an Adhesive Layer

[0117] Two 2″×5″ primed fiber cement specimens (James Hardie, Fontana,Calif.) were arranged with a ⅛″ gap between them. The gap was filledwith 100% polyurethane caulk (Chem-calk 900, Bostik Findley), the caulksurface smoothed, and the caulk allowed to cure overnight. A 2″×3″ pieceof backing material (Sontara 8801 fabric, Dupont) was centered andapplied over the joint, and the surface finished with a medium texture({fraction (1/16)}″) elastomeric latex stucco (Multicoat, Costa Mesa,Calif.). The thickness of the texture coating was from about 0″ to about{fraction (1/16)}″, varying with the texture pattern on the surface. Noadditional adhesive layer was applied between the cementitious board andthe fabric. Instead, the texture coating penetrated the backing materialreaching the fiber cement panel beneath, and adhering the backingmaterial to the panels.

[0118] The sample was equilibrated at 72° F. at 50% relative humidityfor 7 days before tensile testing. The texture coating cracked when thejoint was stretched about 1.6 mm (2.1%) at about 6 mm/min at 72° F.Thus, this type of joint would not withstand the normal expectedmovement of 4′×8′ fiber cement panels, which may shrink 3-5 mm or more(3.9-6.6% for a 3″-wide tape).

[0119] Other fabrics, such as other Sontara Series 8000 polyesterfabrics (Dupont) and nylon fabrics were also tested in this type ofjoint. None withstood more than 3 mm (3.9%) of stretching beforecracking the latex-based texture coating.

EXAMPLE 3 Joint Without a Backing Material

[0120] Two 2″×5″ primed fiber cement specimens (James Hardie, Fontana,Calif.) were arranged with a ⅛″ gap between them. The gap was caulkedand cured as described in EXAMPLE 2. A 2″×3″ layer of 0.028″ thickPVT-3300 adhesive (Carlisle Coating & Waterproofing Inc.) was centeredand applied over the joint. The test sample was finished and the finishcured as in EXAMPLE 2. Tensile testing indicated that the texturecoating cracked when the joint was stretched about 1-2.5 mm (1.3%-3.3%)at 6 mm/min at 72° F. Thus, this type of joint would not withstand thenormal expected movement of 4′×8′ fiber cement panels. Furthermore,because the adhesive layer did not absorb the latex-based texturecoating, the joint was clearly visible after the coating cured.

EXAMPLE 4 Comparative Test of Backing Materials

[0121] A comparative test of backing materials was performed. Thebacking materials were three non-woven polyester fabrics (Sontara 8000,Sontara 8004, Sontara 8801, Dupont). For each test, a joint tape wasprepared from a 2″×3″ piece of the test backing material and a 0.006″layer of a styrene-isoprene-styrene block copolymer adhesive (PL 919,SIA Adhesives). For each test, the edges of two 2″×5″ specimens ofprimed fiber cement panels were butted with no gap between them. Thejoint tape was centered on the joint and applied. The test sample wasfinished and the finish cured as described in EXAMPLE 2.

[0122] The test samples were equilibrated for 7 days at 72° F. at 50%relative humidity. Tensile testing was performed at 6 mm/min at 72° F.,and the strain (stretching) at which the finish cracked was recorded.The properties of the backing materials and test results are provided inTABLE 3. TABLE 3 Elongation Machine Cross Backing Material DirectionDirection Stretch Before Cracking Sontara 8000 38% 114% 10-12 mm(13.1-15.7%) Sontara 8004 33% 110%  9-11 mm (11.8-14.4%) Sontara 880118%  78% 4-7 mm (5.2-9.2%)

[0123] This example shows importance of the elongation of the backingmaterial to the performance of the joint. Because a joint movement of3-5 mm is typical for 4′×8′ panels, the 18% elongation of the Sontara8801 fabric appears to produce an insufficiently flexible joint using a3″-wide tape. Accordingly, we prefer a backing material with anelongation of about 20% or more.

[0124] The methods described below are the preferred methods of joiningbuilding panels with elastomeric joints. These methods preferablycomprise some or all of following steps: applying caulk between adjacentbuilding panels; applying adhesive on a backing material or on the edgesof construction panels such as fiber cement panels; applying a releaseliner on the adhesive applied to the backing material or the edges ofthe panels; removing the release liner and applying an adhesive-coatedbacking material to adjacent fiber cement panels or applying a backingmaterial to adjacent adhesive-coated fiber cement panels.

[0125] In practicing these methods, either a single adhesive or dualadhesives may be used as the adhesives 930 and 940 of FIG. 13 and FIG.14. In a single adhesive system, adhesives 930 and 940 are the sameadhesive. In a dual adhesives system, adhesives 930 and 940 aredifferent adhesives. Preferably, the adhesive 930 is at the centralportion of the joint and adhesive 940 is symmetrically disposed at theedges of the backing material. Adhesive 930 may contact adhesive 940,and in fact, may overlap adhesive 940. In another embodiment, adhesive930 and adhesive 940 do not contact. The thicknesses of the layers ofadhesives 930 and 940 may be the same or different.

[0126] Eleven methods of fabricating an elastomeric joint are describedbelow. The preferred backing material may be the same or different foreach method, and the preferred adhesive(s) may be the same or differentin each method. The building panels for each method may have plainedges, trough edges, embossed edges, or a combination thereof. TABLE 4below provides a brief summary of the first ten methods. TABLE 4Adhesive 930 Adhesive 940 When When Method Location Applied^(a) LocationApplied^(a) Single Adhesive Systems 1 Backing material Before N/A N/A 2Edge of panel Before N/A N/A 3 Backing material After N/A N/A or edge ofpanel Dual Adhesive Systems 4 Backing material Before Backing materialBefore 5 Backing material Before Backing material After or edge of panelBacking material After Backing material Before or edge of panel 6Backing material Before Finish coat is After or edge of panel adhesive140 7 Edge of panel Before Edge of panel Before 8 Edge of panel BeforeBacking material After or edge of panel Backing material After Edge ofpanel Before or edge of panel 9 Backing material After Backing materialAfter or edge of panel or edge of panel 10 Backing material Before Edgeof panel Before Edge of panel Before Backing material Before

[0127] An elastomeric joint for fiber cement panels may be made from asingle adhesive plus a backing material. The adhesive is preferably anelastomeric material that slips with the movement of the building panelsat the center of the joint, but does not slip at the edges of thebacking material. The expected movements of 4′×8′ fiber cement panelswill not crack a flexible texture coating used with this joint system.

METHOD 1

[0128]FIG. 30 illustrates a preferred embodiment of a joint tape 3000made from a backing material 950, a first adhesive 930, a secondadhesive 940, and an optional release liner 990. In METHOD 1 firstadhesive 930 and the second adhesive 940 are the same adhesive. FIG. 15illustrates METHOD 1 for fabricating an elastomeric joint in which thejoint tape 3000 is manufactured in steps 1510 and 1520. The joint tapecan be pre-made, for example, by a tape manufacturer.

[0129] In step 1510, an adhesive layer 930 is applied to a face of abacking material 950. A preferred adhesive is a pressure-sensitiveadhesive, which may include a water-based, solvent-based, or 100%solid-based adhesive. More preferably, the adhesive is a 100%-solid,hot-melt adhesive that does not depend on water or solvent evaporationfor curing. In step 1520, a paper or plastic film 990 coated with arelease agent is optionally laminated to the adhesive layer of the jointtape. A preferred release agent is a silicone-based polymer. Thethickness of release liner is preferably from about 0.0002″ to about0.005″. The release liner is easy to be peeled from the adhesive layerin the application of the joint tape.

[0130] In step 1530, adjacent fiber cement panels 910 are installed asdescribed above. Panels are preferably installed with a ⅛″ gap betweenthe panels to allow for building and panel movement. In anotherpreferred embodiment, the panels 910 are butted together, leaving nogap.

[0131] In step 1540, caulk 920 is optionally applied between panels 910.The caulk is preferably applied flush with the surface of the panels910. The caulk 920, preferably a high solids, non-shrinking, andpermanently flexible caulk made from 100% solid urethane, provides asurface to which the joint tape adheres and provides an even surface,supporting the tape and stucco under tensile and compressive forcesacross the joint.

[0132] In step 1550, the release liner is removed from the elastomericjoint tape and the exposed adhesive face of the joint tape is appliedover the joint between the panels 910. The joint tape is preferablycentered over the joint. The nominal 3″ elastomeric joint tape andflexible stucco finish are capable of withstanding significant jointmovement without cracking the stucco finish.

[0133] Each the following examples uses a 3″-wide backing material ortape to allow direct comparison of the results. Other widths of backingmaterial or tape may also be used.

EXAMPLE 5 Commercial Joint Tape

[0134] A commercially available elastomeric tape used in cementitiouspanel construction (Multicoat, Costa Mesa) is made from Sontara 8801fabric (Dupont) and a butyl-based pressure-sensitive adhesive. Theadhesive on this tape is about 0.01″ thick. Two 2″×5″ pre-coated fibercement board specimens were arranged with a ⅛″ gap between them. The gapwas caulked with a 100% polyurethane caulk (Chem-calk 900, BostikFindley), the caulk surface smoothed, and the caulk allowed to cureovernight. A 2″×3″ piece of Multicoat elastomeric tape was centered andapplied over the caulked joint. The test sample was finished with amedium texture coating (Multicoat, Costa Mesa, Calif.). The thickness ofthe texture coating was about 0 to {fraction (1/16)}″, varying with thetexture pattern on the surface.

[0135] The sample was equilibrated for 7 days at 72° F. at 50% relativehumidity. The texture coating cracked when the joint was stretched about3.5 to 4 mm (4.6-5.2%) at 6 mm/min at 72° F. At 120° F., the texturecoating cracked when the joint was stretched 2 mm (2.6%). The crackingoccurred at the edges of the tape because of slipping of the tape edgeson the panels.

[0136] The joint was also tested statically. In a static test, thesample is rapidly stretched to a predetermined length (over a fewseconds). The sample is held in the stretched state and the timerequired for the finish to crack measured. After stretching the jointabout 2.5 mm (3.3%) at 72° F., the texture coating cracked after 2minutes. Thus, joints made from this commercially available 3″-widejoint tape may not be strong enough to withstand the possible movementof 4′×8′ cementitious panels.

[0137] The 180° peel strength of the Multicoat tape was 10.3 lb/inch at72° F. At 120° F., the 180° peel strength was only about 1 lb/inch.Under water-saturation conditions, the 180° peel strength 4 lb/inch at72° F. In each test, the test speed was 60 mm/min.

EXAMPLE 6

[0138] A joint tape was made with a 0.006″-thick layer of PL919pressure-sensitive adhesive (SIA Adhesives) on 3″-wide piece of Sontara8000 fabric (Dupont). Two 2″×5″ primed cementitious fiber cementspecimens were prepared and caulked as described in EXAMPLE 5. A 2″×3″piece of the joint tape was centered and applied to the joint. The tapewas centered over the caulk joint. The test sample was finished and thefinish cured as described in EXAMPLE 5.

[0139] Under tensile testing at 6 mm/min, the texture coating did notcrack until the joint was stretched about 10-12 mm (13.1-15.7%) at 72°F. The 3″-wide elastomeric joint tape prepared in this example iscapable of withstanding greater than the expected normal movement of4′×8′ fiber cement panels.

[0140] The 180° peel strength of this tape was about 10.6 lb/inch at 72°F. At 120° F., the 180° peel strength was reduced to about 6.4 lb/inch.Under water saturation conditions, the 180° peel strength was about 7lb/inch at 72° F. This joint tape had better heat and water resistancethan the Multicoat tape used in EXAMPLE 5.

EXAMPLE 7

[0141] A joint tape was made with a 0.006″-thick layer of H400 pressuresensitive adhesive (Heartland Adhesives & Coatings) on 3″-wide piece ofSontara 8000 fabric (Dupont). Two 2″×5″ pieces of primed fiber cementpanel (James Hardie, Fontana, Calif.) were butted together, leaving nogap. A 2″×3″ piece of the joint tape was centered and applied to thejoint. The test sample was finished and the finish cured as described inEXAMPLE 5.

[0142] Under tensile testing at 6 mm/min, the texture coating did notcrack until the joint was stretched about 7 mm (9.2%) at 72° F. The3″-wide elastomeric joint tape prepared in this example is capable ofwithstanding greater than the expected normal movement of 4′×8′ fibercement panels.

[0143] The 180° peel strength of this tape was about 10 lb/inch at 72°F. At 120° F., the 180° peel strength was reduced to about 4.7 lb/inch.Under water saturation conditions, the 180° peel strength was about 10lb/inch at 72° F. This joint tape has better heat and water resistancethan the Multicoat tape used in EXAMPLE 5.

[0144] The joint tapes made according to the present disclosure producea joint that is more resistant to cracking than one produced with thecommercial tape at identical tape widths. The selected adhesives endowthe disclosed joint tapes with superior heat and water resistancecompared to the commercial joint tape. Because the normal expectedmovement of 4′×8′ fiber cement panels is 3-5 mm or more (3.9-6.6% for a3″-wide tape), and because a standard joint tape is about 3″ wide, anelastomeric joint preferably withstands greater than 6.6% stretchingwithout cracking, more preferably from about 6.6% to about 20%stretching, wherein the preferred range includes stretching values of7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, and 20%.

[0145] The 180° peel strength at 72° F. is preferably about 10 lb/in orgreater, more preferably about 10.3 lb/in or greater, most preferablyabout 10.6 lb/in or greater. At 120° F, the 180° peel strength ispreferably about 2 lb/in or greater, more preferably about 4 lb/in orgreater, most preferably about 6 lb/in or greater. Under watersaturation conditions at 72° F., the 180° peel strength is preferablyabout 5 lb/in or greater, more preferably, about 6 lb/in or greater,most preferably about 7 lb/in or greater.

METHOD 2

[0146]FIG. 16 illustrates METHOD 2 of making an elastomeric joint, whichdoes not use an adhesive tape. A pressure-sensitive adhesive is appliedto the edges of the front surface of building panels and a release linerlaminated to the adhesive, producing adhesive-edge panels. A preferredembodiment of an adhesive-edge panel is illustrated in FIG. 31A and FIG.31B, which has a panel 910, a first adhesive 930, a second adhesive 940,and a release liner 990. In METHOD 2, the first adhesive and the secondadhesive are the same adhesive. The adhesive and release liner may bepre-applied by the panel manufacturer. The backing material is appliedto the adhesive panels during wall installation. Steps 1610 and 1620describe the manufacture of an adhesive-edge panel. Steps 1630, 1640,and 1650 describe making an elastomeric joint using the adhesive-edgepanels.

[0147] In step 1610, an adhesive layer is applied along an edge of thefront surface of a building panel. Specifications for the adhesive andmethods of applying the adhesive are as described above. Preferably, theadhesive is applied around the perimeter of the front surface of thebuilding panel. The width of the adhesive layer is preferably aboutone-half the width of the backing material, and may be adjusted to takeinto account any gaps to be left between adjacent panels or variabilityin the width of the backing material. The width of the adhesive layermay also be greater than one-half the width of the backing material toassure that the edges of the backing material are completely adhered tothe panel and to allow for small misalignments in the installation ofthe backing material. An adhesive layer that is too wide increasesamount of adhesive and release liner used, however, increasing the cost.Furthermore, foreign materials could potentially adhere to any adhesivethat is not covered by the backing material, possibly affecting theappearance or adhesion of the finish layer. In a preferred embodimentfor making a 3″-wide joint, an adhesive layer of from about 1⅜″ to about1{fraction (9/16)}″, more preferably about 1{fraction (7/16)}″ wide isapplied at each edge.

[0148] In step 1620, a paper or plastic film coated with a release agentis laminated to the adhesive layer on the building panel. Thespecifications for the release liner are provided above. In step 1630,the panels are installed with the adhesive-coated faces facing outwardsas described above. If gaps were left between the building panels, instep 1640, the gaps are optionally caulked as described above.

[0149] In step 1650, the release liner is removed from the adhesive anda backing material is applied to the adhesive. Preferably, the backingmaterial is centered over the joint. Suitable backing materials aredescribed above.

EXAMPLE 8

[0150] A piece of 1{fraction (7/16)}″×2″×0.015″ PL515 adhesive (SIAAdhesives) was applied to an edge of the upper surface of each of two2″×5″ primed fiber cement specimens (James Hardie, Fontana, Calif.). Asheet of silicone-based release liner was applied over the adhesive oneach fiber cement specimen. The adhesive-coated edges were arrangedface-up and adjacent, leaving a ⅛″ gap between the specimens. The jointwas caulked and the caulk cured as described in EXAMPLE 5. Then therelease liner was from the adhesive on the fiber cement specimens. A2″×3″ piece of Sontara 8000 fabric (Dupont) was centered and applied tothe adhesive. The test sample was finished and cured as described forEXAMPLE 5.

[0151] Under tensile testing at 6 mm/min, the texture coating did notcrack until the joint was stretched about 12 mm (15.7%) at 72° F. The3″-wide elastomeric joint prepared in this example is capable ofwithstanding greater than the expected normal movement of 4′×8′ fibercement panels.

METHOD 3

[0152]FIG. 17 illustrates METHOD 3 for making an elastomeric joint, inwhich neither an adhesive tape nor an adhesive panel is prefabricated.Instead, a flexible adhesive layer is applied either to the buildingpanel or to the backing material after the panels have been installedonto a frame. The adhesive may be pressure sensitive or non-pressuresensitive. Preferably, the adhesive is non-pressure sensitive, resultingin a more durable joint. Typically, non-pressure-sensitive adhesives aremore heat and water resistant than pressure-sensitive adhesives. Theadhesive layer may be pre-made as a double-sided tape or an adhesivepaste. In any case, the adhesive should distribute movement of thepanels to the entire backing material, yet not slip from the panel atthe edges of the backing material.

[0153] In step 1710, the panels are installed as described above. Instep 1720, the panels are caulked as described above.

[0154] In step 1730, an adhesive layer is be applied either to theadjacent edges of the panels or to a backing material. Suitableadhesives and methods of applying the adhesive are described above.Preferred adhesives may be the same as or different from the preferredadhesives used in METHOD 1 or METHOD 2.

[0155] In step 1740, either the backing material is applied to theadhesive-covered edges of the panels or the adhesive-coated backingmaterial to the center of the joint. A suitable backing material isselected as described above. If the adhesive is not a pressure-sensitiveadhesive, this step is preferably completed before the adhesive curesexcessively.

EXAMPLE 9

[0156] Two 2″×5″ pre-coated fiber cement board specimens (James Hardie,Fontana, Calif.) were arranged with a ⅛″ gap between them. The gap wascaulked with a 100% polyurethane caulk (Chem-calk 900, Bostik Findley)and the caulk surface smoothed. In this example, the caulk was also usedas the adhesive. A 0.01″ layer of the same caulk was applied to a 2″×3″area centered on the joint. A 2″×3″ piece of Sontara 8004 fabric(Dupont) was applied over the caulking. The test sample was finished andthe finish cured as described in EXAMPLE 5.

[0157] Under tensile testing at 6 mm/min, the texture coating did notcrack until the joint was stretched about 5.2-6.9 mm (6.8-9.1%) at 72°F.

[0158] Multiple adhesives may be used in the disclosed elastomeric jointsystem. In one embodiment, a first adhesive, applied at the center ofthe joint, is an elastomeric material that slips with the movement ofthe panels, distributing the movement to the entire backing material. Asecond adhesive, used at the edges of the joint, is relatively rigid,anchoring the edges of the backing material to the panel. An elastomericjoint made according to this method can withstand large relative panelmovements without cracking the finish coating at any part of the joint,including the edges.

METHOD 4

[0159]FIG. 30 illustrates a preferred embodiment of a joint tape 3000made from a backing material 950, a first adhesive 930, a secondadhesive 940, and an optional release liner 990. FIG. 18 illustratesMETHOD 4, which like METHOD 1 uses a prefabricated adhesive joint tape.The joint tape may be prefabricated by a tape manufacturer. UnlikeMETHOD 1, the joint tape of METHOD 4 uses two adhesives, a firstadhesive 930 used in the center, which is relatively elastomeric, and asecond adhesive 940 used at the edges, which is relatively rigid.Preferred adhesives are pressure sensitive. For a 3″-wide tape, apreferred width of adhesive 930 is from about 0″ to about 3″ and apreferred width of adhesive 940 is from about 0″ to about 3″.

[0160] The steps of METHOD 4 are substantially the same as for METHOD 1.The principal difference between METHOD 4 and METHOD 1 is that METHOD 4uses two adhesives where METHOD 1 uses a single adhesive.

[0161] A joint tape is made in steps 1810 and 1820. In step 1810, afirst adhesive 930 and a second adhesive 940 are applied to a backingmaterial 950. In step 1820, a release liner is optionally laminated tothe adhesives.

[0162] In steps 1830, 1840 and 1850, the joint tape is applied to theseam between adjacent building panels to produce an elastomeric joint.In step 1830, building panels are installed as described above. In step1640, caulk is optionally applied between the building panels, asdescribed above. In step 1850, the release liner is removed from theelastomeric joint tape and the exposed adhesive face of the joint tapeis applied over the joint between the panels. The joint tape ispreferably centered over the joint.

EXAMPLE 10

[0163] A tape was made with PVT-3300 (Carlisle Coating & Waterproofing)and HL 2203 (H. B. Fuller) pressure sensitive adhesives. A2½″-wide×0.028″-thick layer of PVT-3300 adhesive was applied to thecenter of a 3″-wide strip of Sontara 8000 fabric (Dupont). A¼″-wide×0.002″-thick layer of HL 2203 adhesive was applied to both edgesof the fabric. Two 2″×5″ primed fiber cement specimens (James Hardie,Fontana, Calif.) were butted together with no gap and no caulk. A 2″×3″piece of the elastomeric tape was centered over the seam and applied tothe panels. The test sample was finished and the finish cured asdescribed in EXAMPLE 5.

[0164] Under tensile testing at 6 mm/min, the texture coating did notcrack until the joint was stretched about 12-13 mm (15.7-17.1%) at 72°F. The 3″-wide elastomeric joint tape prepared in this example iscapable of withstanding greater than the expected normal movement of4′×8′ fiber cement panels.

EXAMPLE 11

[0165] The experiment of EXAMPLE 10 was repeated except that the tapewas made with only the elastomeric first adhesive. In this example, a3″-wide×0.028″-thick layer of PVT-3300 pressure sensitive adhesive wasused to make the joint tape. No H2203 adhesive was used at the edge.Under the same test conditions, the texture coating cracked at the edgeof the fabric when the joint was stretched about 3-4 mm (3.9-5.2%) at72° F.

[0166] EXAMPLE 10 and EXAMPLE 11 demonstrate the advantages of adual-adhesive system compared to a similar single-adhesive system.

[0167] Note that in EXAMPLE 10 and EXAMPLE 11, the elastomeric joint isfabricated without caulk, i.e., the joint is a caulkless elastomericjoint. This caulkless joint has several advantages over a joint madewith caulk. First, omitting the caulk is less expensive because one neednot obtain the caulk. Second, the caulkless method saves the timerequired to apply the caulk as well as the time required for the caulkto cure. Third, the caulkless method is simpler, both because one neednot apply any caulk, and because the panels may be butted together,eliminating the step of positioning the panels with gaps.

METHOD 5

[0168]FIG. 19 illustrates METHOD 5 of making an elastomeric joint. As inMETHOD 1 and METHOD 4, a joint tape is prefabricated, then applied tothe joint. In a preferred embodiment, the joint tape is pre-made by atape manufacturer. Unlike the joint tape of METHOD 4, which is a dualadhesive tape, the joint tape of METHOD 5 is a single adhesive tape. Theadhesive 930 in the joint tape of METHOD 5 is pre-applied down thecenter of the backing material, with no adhesive at the edges. Thesecond adhesive 940 is applied during the installation of the wallsystem either to the backing material or to the building panels.

[0169] In an alternative embodiment, the joint tape is prefabricatedwith the second adhesive 940 applied to the edges of the backingmaterial. In this embodiment, the first adhesive 930 is applied duringthe installation of the wall system either to the center of the bakingmaterial or to the building panels.

[0170] Preferably, the adhesive applied to the backing material in thejoint tape manufacturing process is pressure sensitive. The adhesiveapplied during the installation of the wall system may be pressuresensitive or non-pressure sensitive. More preferably, the joint tape ismanufactured with the first adhesive 930, the more elastomeric adhesive,applied down the center of the backing material. In this embodiment, thesecond adhesive 940 is preferably a non-pressure-sensitive adhesivebecause a wider range of non-pressure-sensitive adhesives produce thedesired strong bond between the panel and the edges of the backingmaterial. For a 3″-wide tape, the preferred width of adhesive 930 isfrom about 0″ to about 3″, and the preferred width of adhesive 940 isfrom about 0″ to about 3″, wherein the sum of the widths of the twoadhesives is 3″. The following procedure describes an embodiment inwhich the first adhesive 930 is used to manufacture the joint tape.

[0171] The joint tape is manufactured in steps 1910 and 1920. In step1910, first adhesive 930 is applied down the center of the backingmaterial 950. Selection of adhesive and the backing material, andapplication of the adhesive is described above. In step 1920, a releaseliner is optionally laminated to the adhesive.

[0172] In step 1930, building panels are installed as described above.In step 1940, caulk is optionally applied between the building panels,as described above. In step 1950, second adhesive 940 is applied to thepanel at a location corresponding to the edges of the installed backingmaterial or applied to the edges of the backing material of the jointtape manufactured in steps 1910 and 1920. The second adhesive 940 isapplied as described above. Preferably, the second adhesive 940 isnon-pressure sensitive. The second adhesive 940 may be applied eitherbefore or after the joint tape has applied to the joint.

EXAMPLE 12

[0173] A 2½″-wide×0.028″-thick layer of PVT-3300 pressure sensitiveadhesive (Carlisle Coating & Waterproofing) was applied down the centerof a 2″×3″ piece of Sontara 8000 fabric (Dupont), leaving about a ¼″ ofeach 2″ edge of the fabric was free of adhesive. Two 2″×5″ specimens ofprimed fiber cement panels were butted together, leaving no gap. Nocaulk was applied. The elastomeric joint tape was centered and appliedto the joint. To each edge of the backing material was applied a¼″-wide×0.002″-thick layer of UR-0210 moisture-cured polyurethane (H. B.Fuller), and the edges applied to the panels. The test sample wasfinished and the finish cured as described in EXAMPLE 5.

[0174] Under tensile testing at 6 mm/min, the texture coating did notcrack until the joint was stretched about 12-13 mm (15.7-17.1%) at 72°F. At 120° F., the texture coating cracked when the joint was stretched13 mm (17.1%), indicating the heat resistance of this joint. The 3″-wideelastomeric joint tape prepared in this example is capable ofwithstanding greater than the expected normal movement of 4′×8′ fibercement panels.

[0175] The Sontara fabrics (Dupont) work well as the backing material,although other stretchable fabrics are also suitable. The experiment inEXAMPLE 12 was repeated with a polyamide (Nylon) fabric in EXAMPLE 13.

EXAMPLE 13

[0176] A 2½″-wide×0.028″-thick layer of PVT-3300 pressure sensitiveadhesive was applied down the center of a 3″-wide piece of Nylon meshP2017 (Applied Extrusion Technologies), leaving about a ¼″ of each 2″edge of the fabric was free of adhesive. Two 2″×5″ specimens of primedfiber cement panels were butted together, leaving no gap. No caulk wasapplied. The elastomeric joint tape was centered and applied to thejoint. To each edge of the backing material was applied a¼″-wide×0.002″-thick layer of UR-0210 moisture-cured polyurethane (H. B.Fuller), and the edges applied to the panels. The test sample wasfinished and the finish cured as described in EXAMPLE 5.

[0177] Under tensile testing at 6 mm/min, the texture coating did notcrack until the joint was stretched about 7-11 mm (9.2-14.4%) at 72° F.The 3″-wide elastomeric joint tape prepared in this example is capableof withstanding greater than the expected normal movement of 4′×8′ fibercement panels.

[0178] Non-stretchable and semi-stretchable fabrics such as non-wovenglass fiber fabric that were tested were unable to withstand large jointmovements. A representative test is provided in EXAMPLE 14.

EXAMPLE 14

[0179] A 2½″-wide×0.028″-thick layer of PVT-3300 pressure sensitiveadhesive (Carlisle Coating & Waterproofing) was applied down the centerof a 3″-wide piece of non-woven glass-fiber fabric (M524-C33, OwensCorning) leaving about a ¼″ of each 2″ edge of the fabric was free ofadhesive. Two 2″×5″ specimens of primed fiber cement panels were buttedtogether, leaving no gap. No caulk was applied. The elastomeric jointtape was centered and applied to the joint. To each edge of the backingmaterial was applied a ¼″-wide×0.002″-thick layer of UR-0210moisture-cured polyurethane (H. B. Fuller), and the edges applied to thepanels. The test sample was finished and the finish cured as describedin EXAMPLE 5.

[0180] Under tensile testing at 6 mm/min, the texture coating crackedwhen the joint was stretched about 1.8 mm (2.4%) at 72° F. The 3″-widejoint tape prepared in this example is incapable of withstanding greaterthan the expected normal movement of 4′×8′ fiber cement panels.

METHOD 6

[0181]FIG. 20 illustrates METHOD 6 of making an elastomeric joint, whichis similar to METHOD 5, except that the second adhesive 940 is notapplied to the backing material or panels in a step analogous to step1950 of METHOD 5. Instead, METHOD 6 uses a backing material that allowsthe finish coating to permeate the fabric and to bond to the buildingpanels. As such, the finish coating serves as the second adhesive 940,eliminating a separate application step. For a 3″-wide tape, thepreferred width of adhesive 930 is from about 0″ to about 3″.

[0182] In step 2010, first adhesive 930 is applied down the center ofthe backing material 950. The backing material is permeable to theelastomeric finish coat. Selection and application of the adhesive isdescribed above. In step 1820, a release liner is optionally laminatedto the adhesive 930.

[0183] In step 2030, building panels are installed as described above.In step 2040, caulk is optionally applied between the building panels,as described above. In step 2050, the release liner is removed from theelastomeric joint tape and the exposed adhesive face of the joint tapeis applied over the joint between the panels. The joint tape ispreferably centered over the joint. In step 2060, an elastomeric finish980 is applied to the panelized wall system. The finish permeates thebacking material 950, functioning as the second adhesive 940.

[0184] In alternative embodiment of METHOD 6, a strip of the firstadhesive 930 that is narrower than the backing material is applied toadjacent edges of the building panels. A backing material that ispermeable to the elastomeric finish coating is then centered and appliedto the joint, leaving the edges of the backing material free ofadhesive. The texture coating applied to the entire wall permeates thebacking material, functioning as the second adhesive 940. For 3″-widebacking material, the preferred width of adhesive 930 is from about 0″to about 3″. Where the first adhesive 930 is 3″-wide, the same width asthe backing material, METHOD 6 is the same as METHOD 1.

EXAMPLE 15

[0185] A 2½″-wide×0.028″-thick layer of PVT-3300 pressure sensitiveadhesive (Carlisle Coating & Waterproofing) was applied down the centerof a 3″-wide piece of Sontara 8801 fabric (Dupont), leaving about a ¼″of each 2″ edge of the fabric was free of adhesive. Two 2″×5″ specimensof primed fiber cement panels were arranged with a ⅛″ gap. No caulk wasapplied to the gap. The elastomeric joint tape was centered and appliedto the joint. The test sample was finished and the finish cured asdescribed in EXAMPLE 5.

[0186] Under tensile testing at 6 mm/min, the texture coating did notcrack until the joint was stretched about 9-13 mm (11.8-17.1%) at 72° F.The 3″-wide elastomeric joint tape prepared in this example is capableof withstanding greater than the expected normal movement of 4′×8′ fibercement panels.

METHOD 7

[0187]FIG. 21 illustrates METHOD 7 for making an elastomeric joint,which is similar to METHOD 2 in that an adhesive joint tape is notpre-made. Instead, pressure-sensitive adhesives are applied to the edgesof the front faces of the building panels and a release liner islaminated to these adhesive-edge panels. The adhesive-edge panels may beprefabricated by the panel manufacturer. After the panels are fastenedto the frame, the backing material is applied to the adhesive ofadjacent panels. A preferred embodiment of an adhesive-edge panel isillustrated in FIG. 31A and FIG. 31B, which has a panel 910, a firstadhesive 930, a second adhesive 940, and a release liner 990. UnlikeMETHOD 2, which uses a single adhesive, METHOD 7 uses two adhesives, amore elastomeric first adhesive 930, applied at the center of the joint,and a more rigid second adhesive 940, applied at the edges of the joint.Preferably, both adhesives 930 and 940 are pressure sensitive.

[0188] For a 3″-wide backing material, the preferred width of adhesive930 on each panel is from about 0″ to about 1½″ and the preferred widthof adhesive 940 on each panel is from about 0″ to about 1½″, wherein thesum of the widths is about 1½″. As would be apparent to one skilled inthe art, the sum of the widths may be smaller if adjacent panels areinstalled with a gap. METHOD 7 is the same as METHOD 2 if the width ofeither the first adhesive 930 or the second adhesive 940 is 0″.

[0189] In step 2110, a first adhesive 930 is applied along an edge ofthe front surface of a building panel and a second adhesive 940 isapplied adjacent to the first adhesive 930, away from the edge of thepanel. Specifications for the adhesives and methods of applying theadhesive are as described above. Preferably, the adhesive is appliedaround the perimeter of the front surface of the building panel. In apreferred embodiment, the total width of the adhesive layers is about1{fraction (7/16)}″ wide at the edge for making a 3″-wide elastomericjoint.

[0190] In step 2120, a release liner is laminated to the adhesive layeron the building panel. The specifications for the release liner areprovided above.

[0191] In step 2130, the panels are installed with the adhesive-coatedfaces facing outwards as described above. In step 2140, the gaps betweenthe installed building panels are optionally caulked as described above.In step 2150, the release liner is removed and the backing material isapplied to the exposed adhesive. Preferably, the backing material iscentered over the joint. Suitable backing materials are described above.

EXAMPLE 16

[0192] The same methods and materials used in EXAMPLE 10 (METHOD 4) wereused in EXAMPLE 16, except that the adhesives were applied to the fibercement panels instead of to the backing material. Under tensile testingat 6 mm/min, the texture coating did not crack until the joint wasstretched about 12-13 mm (15.7-17.1%) at 72° F. The 3″-wide elastomericjoint prepared in this example is capable of withstanding greater thanthe expected normal movement of 4′×8′ fiber cement panels.

METHOD 8

[0193]FIG. 22 illustrates METHOD 8 of making an elastomeric joint, whichis similar to METHOD 7 except that only one adhesive is pre-applied tothe building panels. The adhesive may be pre-applied by the panelmanufacturer.

[0194] In METHOD 8, a first adhesive 930 is applied to the part of theedge on the front face of a panel that will become the center of thejoint. The second adhesive 940 is applied either to the backing materialor to the part of the panel corresponding to the edge of the jointduring wall installation. In another embodiment, the second adhesive 940is pre-applied to the panel before installation, and first adhesive 930is applied to the backing material or to the panel during the wallinstallation. Preferably, the pre-applied adhesive is pressuresensitive. The later applied adhesive may be pressure sensitive ornon-pressure sensitive. More preferably, first adhesive 930 is thepre-applied adhesive and second adhesive 940 is the later appliedadhesive. In this embodiment, the second adhesive 940 is preferably anon-pressure-sensitive adhesive because a wider range ofnon-pressure-sensitive adhesives produce the desired strong bond betweenthe panel and the edges of the backing material. For a 3″-wide joint,the preferred width of the first adhesive 930 on each panel is fromabout 0″ to 1½″, and the preferred width of the second adhesive 940 oneach panel is about 0 to 1½″, wherein the sum of the widths about 1½″.

[0195] In step 2210, a first adhesive 930 is applied along an edge ofthe front surface of a building panel to an area corresponding to thecenter of the joint. Specifications for the adhesives and methods ofapplying the adhesive are as described above. Preferably, the adhesiveis applied around the perimeter of the front surface of the buildingpanel. In a preferred embodiment, the total width of the adhesive layersis about 1{fraction (7/16)}″ wide at the edge for making a 3 ″-wideelastomeric joint.

[0196] In step 2220, a release liner is laminated to the adhesive layeron the building panel. The specifications for the release liner areprovided above.

[0197] In step 2230, the panels are installed with the adhesive-coatedfaces facing outwards as described above. In step 2240, the gaps betweenthe installed building panels are optionally caulked as described above.In step 2250, a second adhesive 940 is applied to the edges of a backingmaterial 950 or to the portion of the panel corresponding 910 to theedge of the joint. In step 960, the release liner is removed and thebacking material is applied to the exposed adhesive. Preferably, thebacking material is centered over the joint. Suitable backing materialsare described above.

[0198] In an alternative embodiment, the second adhesive 940 is appliedin step 2010 to the area on an edge of the panel 910 corresponding tothe edge of the joint. In step 950, the first adhesive 930 is applied toeither the center of the backing material 950 or to the portion of thepanel 910 corresponding to the center of the joint.

METHOD 9

[0199]FIG. 23 illustrates METHOD 9 of making an elastomeric joint, whichis similar to METHOD 3 in that adhesive is not pre-applied either to thebacking material or to the panels. The difference between METHOD 9 andMETHOD 3 is that METHOD 9 uses two adhesives while METHOD 3 uses asingle adhesive. The adhesives may be applied either to the backingmaterial or to the panels. Either adhesive layer may be made into adouble-side tape or an adhesive paste. In another embodiment, bothadhesives are incorporated into a single double-sided tape. For a3″-wide joint, the preferred width of the first adhesive 930 is fromabout 0″ to about 3″ and the preferred width of the second adhesive 940is from about 0″ to about 3″, wherein the sum of the widths of the twoadhesives is about 3″.

[0200] In step 2310, the panels are installed as described above. Instep 2320, caulk is optionally applied to any gaps left between thepanels.

[0201] In step 2330, a first adhesive 930 and a second adhesive 940 areapplied to a backing material 950 or to the area of the panels 910corresponding to the joint. In either case, the first adhesive 930 isapplied to the area corresponding to the center of the joint and thesecond adhesive is applied to the area corresponding to the edges of thejoint. The first adhesive 930 may be applied before, after, or at sametime as the second adhesive 940.

[0202] In step 2340 the backing material with the preapplied adhesive isapplied to the joint between adjacent panels, or a backing material isapplied to the adhesive that was preapplied to the panels. Preferably,the backing material is centered over the joint in either case.

EXAMPLE 17

[0203] Two 2″×5″ specimens of primed fiber cement panels were arrangedwith a ⅛″ gap between them. The gap was caulked and the caulk cured asdescribed in EXAMPLE 5. A 2½″-wide×0.02″-thick layer of HL2203 adhesive(H. B. Fuller) was applied to the panels centered on the joint. A¼″-wide×0.002″-thick layer of UR-0210 moisture-cured polyurethaneadhesive (H. B. Fuller) was applied on the panels on each side of theHL2203 adhesive. A 2″×3″ piece of Sontara 8000 fabric was applied to theadhesives. The test sample was finished and the finish cured asdescribed in EXAMPLE 5.

[0204] Under tensile testing at 6 mm/min, the texture coating did notcrack until the joint was stretched about 16 mm (21.0%) at 72° F. The3″-wide elastomeric joint prepared in this example is capable ofwithstanding greater than the expected normal movement of 4′×8′ fibercement panels.

METHOD 10

[0205]FIG. 24 illustrates METHOD 10 of making an elastomeric joint,which uses both an adhesive joint tape and adhesive-edge panels. Thefirst adhesive 930 is pre-applied either to the backing material or toan edge of the front of the panel. The second adhesive 940 ispre-applied to an edge of the front of the panel if the first adhesiveis pre-applied to the backing material, or to the backing material ifthe first adhesive is pre-applied to a edge of the front of the panel.Both adhesives are preferably pressure sensitive. For a 3″-wide joint,the preferred width of the first adhesive 930 is from about 0″ to about3″ and the preferred width of the second adhesive 940 is from about 0″to about 3″, wherein the sum of the widths of both adhesives is about3″. METHOD 10 is the same as METHOD 4 if both adhesives are pre-appliedto the backing material and METHOD 7 if both adhesives are pre-appliedto the front edges of the building panel.

[0206] In step 2410, a first adhesive 930 is applied down the center ofthe backing material 950. In step 2420, a release liner is optionallylaminated to the first adhesive.

[0207] In step 2430, a second adhesive is applied to an area of a panel910 corresponding to the edge of the joint. In step 2440, a releaseliner is laminated to the second adhesive.

[0208] In step 2450, the adhesive-edge building panels produced in steps2430 and 2440 are installed as described above. In step 2460, caulk isoptionally applied between any gaps between the panels. In step 2470,the release liners are removed from the panels and the joint tape, andthe joint tape is applied to the joint. Preferably, the joint tape iscentered over the joint.

METHOD 11

[0209] An elastomeric joint fabricated according to METHOD 11 isillustrated in FIG. 25. Elastomeric joint 900 includes two buildingpanels 910, a flexible first adhesive layer 930, rigid second adhesivelayers 940, a backing material 950, and a joint filler 970. The panelsand elastomeric joint are optionally finished with a texture coating980. The panels 910 illustrated in FIG. 25 have embossed edges andtrough edges 960; however, flat panels as well as panels with onlyembossed edges may also be used in this method. In METHOD 11, anelastomeric joint constructed according to any of METHOD 1 throughMETHOD 10 is covered with a joint filler 970. In the embodimentillustrated in FIG. 25, substantially no gap is provided between thepanels 910, and accordingly, no caulk is used.

[0210]FIG. 26 illustrates METHOD 11 of constructing an elastomericjoint. In step 2610, an elastomeric joint is fabricated at the jointbetween adjacent building panels according to any of METHOD 1 throughMETHOD 10. In step 2620, a layer of joint filler 970 is applied to coverthe backing material 950. In a preferred embodiment, the joint filler970 is a ceramic putty.

[0211] The joint filler 970 simplifies the production of a panelizedwall with a monolithic appearance. The joint filler provides anothercomponent in the elastomeric joint system for distributing the relativemovements of adjacent panels. As is well known in the are, the jointfiller may be used to cover the edges of the backing material as well asto fill any depressions in the joint or trough areas, providing a smoothsurface for subsequently applied texture coatings. The joint filler maybe tooled during application or may be sanded after curing to provide asmooth surface. As illustrated in FIG. 25, METHOD 11 is a preferredmethod when used in conjunction with trough-edge panels. Moreover,METHOD 11 is advantageously applied to wall systems constructed frompanels with embossed edges or other edge profiling because the depth ofthe embossing need not closely match the total thickness of the backingmaterial and adhesive. Also the width of the embossing need not closelymatch the width of the backing material, especially important becausethe panels may be installed either without gaps or with gaps of varyingwidth. METHOD 11 is also advantageously be used with flat-edge orplain-edge panels.

[0212] In a preferred embodiment of METHOD 11, a second joint filler,preferably an elastomeric joint filler, is applied over the first jointfiller, as described above.

[0213]FIG. 27 is an elevation view of a panelized wall system 2700composed of a frame 2710, building panels 2720, elastomeric joints 2730,and fasteners 2740.

[0214]FIG. 28 illustrates the construction of a panelized wall systemaccording to METHOD 11. In step 2810, the back surfaces of buildingpanels 2720 are positioned over a frame 2710 as described above. Thebuilding panels are preferably fiber cement, and may be flat, havetrough edges, or embossed edges. The frame is optionally equipped with amoisture barrier, for example asphalt paper, a water break, or both. Thepanels are positioned over the optional moisture barrier and waterbreak. The panels may be positioned with gaps between adjacent panels orbutted, i.e., with no gaps between adjacent panels, as described above.

[0215] In step 2820, the panels 2720 are attached to the frame 2710 withfasteners 2740 as described above. If gaps were left between adjacentpanels in step 2810, in step 2830, caulk is optionally applied to fillthe gaps. In step 2840, a backing material is adhered to the jointsbetween the panels 2720. Steps 2810-2840 may be performed according toany of METHOD 1 to METHOD 10.

[0216] In step 2850, a joint filler is optionally applied over thebacking material, as described above. In step 2860, an elastomericfinish is applied to the entire panelized wall system as describedabove.

EXAMPLE 18

[0217] A wall was framed with 2″×4″ lumber, studs 16″-on-center. Asphaltpaper and a water break (Homeslicker Rain Screen, Benjamin Obdyke,Horsham, Pa.) were installed on the frame. The back surfaces of 4′×8′×⅝″trough-edge fiber-cement panels were positioned over the frame level andplumb, with the edges of adjacent panels sharing a stud. The troughdepth was 0.077″, the trough-edge offset was 1½″, and the trough widthwas ¾″. The edges of the panels butted together leaving no gaps. Thepanels were nailed to the frame. The joints between the panels weretaped with a tape made from 3″-wide Sontara 8804 fabric (DuPont) and a0.010″-thick layer of Heartland Adhesive H400 (styrene-butadiene). Thetaped joints were then covered with a smooth, flat layer of a ceramicputty joint filler (Fill-n-Build, Global Coatings), which was allowed tocure for 1 to 2 hours. The joint filler was then covered with a smooth,flat layer of an elastomeric joint filler (Acracream, Global Coatings).The wall was allowed to cure for a minimum of about 24 hours.

[0218] A stucco covering was then applied to the wall. First, ColorsealPlus Primer (Global Coatings) was applied to the entire wall surfacewith a paint roller and allowed to dry for 1 to 2 hours. Next, Carraratexture (Global Coatings) was shot onto the wall with a hopper gun. Atthis point, the surface may be left “as is” for a “sanded” finished orhand-troweled to the desired finish. The stucco finish was protecteduntil cured.

EXAMPLE 19

[0219] A panelized wall was constructed according to EXAMPLE 18 exceptthat the frame included 4′×8′×½″ OSB shear panels attached to the studs,followed by the asphalt paper and the water break.

EXAMPLE 20

[0220] The comparative performances in a racking test of a wallconstructed according to the preferred method disclosed in U.S. Pat. No.5,732,520 and a wall constructed according to the present disclosurewere evaluated in this test.

[0221] The test walls were constructed in a testing device as describedin ASTM E 72-(98). The walls were 8′×8′ walls framed with 2″×4″ lumber,studs 16″-on-center. Two fiber-cement panels with plain edges,4′×8′×{fraction (5/16)}″ (Hardiepanel, James Hardie, Fontana, Calif.),were positioned on the frame, their adjacent edges sharing a stud with a⅛″ gap between them. The panels were attached to the frame. The gapbetween the panels was caulked with Chem-calk 900 (Bostik Findley), thesurface of the caulk smoothed, and the caulk allowed to cure overnight.The joints were then taped with either the joint tape of U.S. Pat. No.5,732,520 or a joint tape according to the present disclosure. Thejoints were finished with a smooth stucco coating (Multitex, Multicoat,Costa Mesa, Calif.). Finally, both walls and joints were finished with amedium texture stucco coating (Multitex, Multicoat, Costa Mesa, Calif.).

[0222] The joint tape of U.S. Pat. No. 5,732,520 is a commerciallyavailable 3″-wide self-adhesive joint tape (Multicoat, Costa Mesa,Calif.) made from Sontara 8801 fabric (Dupont) and a butyl-basedpressure sensitive adhesive. The joint tape of the present disclosure isa 3″-wide self-adhesive joint tape made from Sontara 8004 fabric and a0.010″-thick layer of Heartland Adhesive H400 (styrene-butadiene).

[0223] Each wall was subjected to a racking load according to the testmethod. The results are provided in FIG. 29. The wall constructedaccording to the disclosed method withstood a higher racking load anddeflection before cracking at the panel joints.

[0224] The embodiments illustrated and described above are provided asexamples of certain preferred embodiments of the present invention.Various changes and modifications can be made to the embodimentspresented herein by those skilled in the art without departure from thespirit and scope of this invention, the scope of which is limited onlyby the claims appended hereto.

What is claimed is:
 1. A trough-edge building panel comprising abuilding panel comprising a front surface, a back surface, and aplurality of edges and a trough on the front surface of the panelextending along an edge of the panel, wherein the trough is spacedinwardly from the edge of the panel by a trough edge offset, the troughis sized and configured to accept an edge of a backing material appliedover a seam between adjacent panels, and the trough comprises a wall anda floor, wherein a side of the trough proximate to the edge of the panelforms the wall, wherein the height of the wall is a trough depth, thefloor of the trough is lower than a surface of the panel between thewall of the trough and the edge of the panel, and the width of the flooris a trough width.
 2. The trough-edge panel of claim 1, wherein thepanel is fiber cement.
 3. The trough-edge panel of claim 2, wherein thepanel is about 4′ by about 8′.
 4. The trough-edge panel of claim 2,wherein the panel is from about {fraction (3/16)}″ to about 2″ thick. 5.The trough-edge panel of claim 2, wherein the trough edge offset is fromabout ½″ to about 3″, the trough depth is from about 0.005″ to about0.25″, and the trough width is from about ⅛″ to about 2″.
 6. Thetrough-edge panel of claim 2, further comprising a surface offset depthof from 0″ to about 0.1″.
 7. The trough-edge panel of claim 1, whereinthe trough is formed by embossing, using a plate press, using a profiledaccumulator roll in the Hatschek process, or by post-cure machining. 8.A method of fabricating a trough-edge building panel comprising:creating a trough on the front surface of a building panel extendingalong an edge of a panel, wherein the trough is spaced inwardly from theedge of the panel by a trough edge offset, the trough is sized andconfigured to accept an edge of a backing material applied over a seambetween adjacent panels, and the trough comprises a wall and a floor,wherein the side of the trough proximate to the edge of the panel formsthe wall, wherein the height of the wall is a trough depth, the floor ofthe trough is lower than the surface of the panel between the wall ofthe trough and the edge of the panel, and the width of the floor is atrough width.
 9. The method of claim 8, wherein the panel is fibercement.
 10. The method of claim 9, wherein the panel is about 4′ byabout 8′.
 11. The method of claim 9, wherein the panel is from about{fraction (3/16)}″ to about 2″ thick.
 12. The method of claim 9, whereinthe trough edge offset is from about ½″ to about 3″, the trough depth isfrom about 0.005″ to about 0.25″, and the trough width is from about ⅛″to about 2″.
 13. The method of claim 9, further comprising a surfaceoffset depth of from 0″ to about 0.1″.
 14. The method of claim 8,wherein the trough is formed by embossing, using a plate press, using aprofiled accumulator roll in the Hatschek process, or by post-curemachining.